1. Field of the Invention
The present invention relates generally to communications links and more specifically relates to a communication link in which pulsed data is transmitted in the form of infrared radiation between a fixed station and an automatically guided vehicle.
2. Description of the Prior Art
Automatically guided vehicles are well-known in the art and one type is generally described in U.S. Pat. Nos. 3,935,922, 3,970,840, 4,003,445, 4,020,918, 4,034,823, 4,307,791, 4,341,985, 4,379,497 and 4,397,372. These patents disclose an automatically guided vehicle which follows a guide line that contains material that emits electromagnetic radiation. The electromagnetic radiation can be detected by a photocell sensor. The automatically guided vehicle is also controlled by a radio frequency communication link.
These automatically guided vehicles controlled by radio frequency signals are used in warehouses and for "on command" travel from place to place in a factory for parts delivery. The radio frequency signals are serial in nature, slow in the amount of information transmitted, and may be subjected to electromagnetic interference from other equipment used in the factory environment. Typically the radio frequency signals are used for vehicle navigation, guidance and collision avoidance.
It can be appreciated, therefore, that in a highly automated factory the communications link for these vehicles possess inherent shortcomings. Accordingly, there is a need for a communication link which is not susceptible to electromagnetic interference and which can transmit the large amounts of data associated with automated devices.